Fuel pump



June 24, 1941. w. J. WAGNER 2 Sheets-Sheet 1 IN VENTOR.

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ATTOR Y5.

BY. #2, V

June 24, 1941. w, J, WAGNER FUEL PUMP Filed Oct 20, 19:58 2 Sheets-Sheet 2 INVENTOR. Wz/Zuzmj Wqgizelr BY ATTO .9v

Patented June 24, 1941 UNITED STATES PATENT OFFICE FUEL PUMP William J. Wagner, Chicago, Ill. Application October 20, 1938, Serial No. 235,923

Claims.

The invention relates to pumps and has more particular reference to an improved fuel pump for supplying oil to the nozzle of an oil burner.

An object of the invention is to provide a fuel pump which will maintain a steady oil pressure at the burner nozzle; which will control the admission of the fuel to the nozzle following operation of the pump after a period of rest and which will also cut off the fuel as the burner shuts down; which will thoroughly strain the oil delivered under pressure to the nozzle: and which will either return the oil in excess of that used at the nozzle to the storage tank or recirculate the same within the pump. A more specific object is to provide afuel pump in which the piping for conducting the oil to and from the pump has connection with the pump casing so that the front cover thereof can be easily removed, and wherein the pump unit, driving shaft, seal and strainer are constructed so that they can be withdrawn as a single unit through the opening thus provided without disturbing the piping connections.

Another object is to provide a fuel pump of the positive displacement type which will incorporate a flexible diaphragm forming one wall of a pressure chamber to thereby eliminate pump pulsations and which diaphragm will also carry one member of a valve controlling the flow of the oil to the nozzle.

Another object is to provide a fuel pump having an adjustable valve in the removable frontcover of the casing for controlling the pump pressure.

A further object is to provide a fuel pump having novel safety features wherein the pumping unit thereof may move in a direction axially of the driving shaft and which unit is yieldingly held in position by a coil spring that also seats the stationary member of the shaft seal. present device the pump housing having the cover plate of the pump fixed thereto is free to rotate within the casing although during normal operation of the pumping elements the coil spring will hold the said housing, preventing rotation thereof. However, should the pump gears freeze or in the event excessive hydraulic pressure develops the pumping unit including the elements and the housing therefor will revolve with the shaft and thus eliminate damage to these elements.

A further ,object resides in the provision of a fuel pump wherein the said coil spring which yleldingly positions the pumping unit provides a force reacting against the hydrostatic pressure developed by the pump to thus control admission and cut-off of the fuel flow to the nozzle.

Another object is to providea fuel pump wherein the driving shaft thereof may be rotated in either direction for pumping and which merely requires that the pump cover plate be revolved 180 degrees to reverse the position of the suction and In the view taken substantially through the center of a fuel pump constructed in accordance with the present invention;

Figure 2 is a horizontal longitudinal sectional view taken substantially along line 2-2 of Figure 1;

Figure 3 is a front elevational View of the present pump showing the construction of the front cover for the pump casing and the manner of releasably securing the same in position;

Figure 4 is a fragmentary detail view taken substantially along line 4-4 of Figure 2 and showing the pumping elements of the present device;

Figure 5 is a plan view showing the inside surface of the cover plate for the pump housing; and Figure 6 is a fragmentary sectional view taken substantially along line 6-6 of Figure 3 showing the port for lay-passing the oil.

Referring to the drawings, the present pump consists of a pump casing identified in its entirety by numeral l0, Figures 1 and 2, which has formed integral therewith wing portions 1 I provided with openings I2 for securely bolting the casing to a stationary support. The casing is tubular and has a forwardly extending portion identifled'by numeral l3 within which is located the strainer for the oil, the diaphragm and the pumping elements including the pump housing and gears, all of which will be presently described in detail. To the rear of the wing portions the casing provides a part l4 within which is located the stationary 'member for the shaft seal and said shaft seal.

The rear of said part I4 is closed by cover i5. The forward portion is of the casing has also formed integral therewith the suction port l6, Figure 3, the nozzle port l1 and the by-pass port Hi. The piping for conducting the oil to and from the pump is connected to said ports and these connections need not be disturbed since the easing is provided with a removable front cover, identified in its entirety by numeral Ell, which permits removal of the pumping elements from within the casing.

Said cover, as shown in Figures 1, 2 and 3, is releasably secured to the casing by the screws 2i which are fairly heavy and adequate in number since the full hydrostatic pressure of the pump is against this front cover. On the inside surface of the cover the same is provided with an annular machined surface 22, Figure 2, and a recess 23, which is provided at its center with a somewhat deeper recess 24. On the exterior face of the front cover is provided ports 25 and 26, Figure 3, the former communicating with the interior of the pump and providing means for attaching a vacuum gauge for indicating the suction pressure of the pump. Port 26 communicates with the pressure side of the pump and therefore indicates the pressure of the oil being pumped thereby. Said ports may be closed by plugs 21 when gauges are not connected thereto. The cylindrical portion 28, also formed integral with said cover on its exterior face, provides the chamber 29 having connection at its lower end through the passage 30 with the pressure side of the pump and connecting at its upper end through passage 3| with the by-pass port l8, Figure 6. The cone valve 32 held in position by the coil spring 33 controls the flow of oil from the pressure side of the pump through passage 30 to the by-pass port including passage 3|. The tension exerted by the coil spring 33 on the cone valve 32 may be adjusted by member 34 which is threaded in the upper end of the chamber 29. The interior of said chamber is normally sealed from the atmosphere by the nut 35.

The suction port It has connection with chamber 36, Figures 1 and 2, provided by the interior wall of the casing and which chamber receives the filtering screens 31 and 38. The filtering screen 3'! is provided at its forward end with the ring 40 which has a sealing fit with the wall of said suction chamber. The other end of said screen is positioned to the rear of said chamber by the ring M and to this end is suitably secured the rear end of screen 38. The forward end of said screen 38 is formed with a ring 52, which ring has a sealing fit with the periphery of the pump housing indicated by numeral d3. Said housing is concentrically positioned within chamber 36 as a result of the surfaces 46 with which the portions 65 of said housing have a sliding fit.

Although the exterior surfaces of the pump housing are concentric with the casing the bore therethrough is eccentric. Said bore toward the rear of the member receives part Q of the pump which has a press fit therein and which part provides the crescent 41, Figure 4. Said crescent occupies the forward portion of the bore and has associated therewith the internal gear &8 and pinion 49. S'aid gears together with the crescent comprise the pumping elements of the present device, the said pinion having a substantially rectangular opening extending therethrough for receiving the forward end of the driving shaft 50. As the shaft is rotated the pinion l3 likewise rotates, producing rotation of the eccentric ring on the interior surface of which is the internal gear d8. Movement of the gear teeth with respect to the crescent 41 functions to pump the oil to a relatively high pressure.

The pump housing $3 is provided with a cover plate 5!, shown in detail in Figure 5,, and which is nonrotatably held inproper position to'the front of said housing by the screw 52, Figure 2. Said screw is threaded in the face of said housing and its head has engagement with the cover plate to thereby hold the cover plate, preventing rotation of the same with respect to the housing. As best shown in Figure 5 the inside surface of said cover plate is formed with a pair of recesses 53 and 5d,

respectively, the former having association with the suction side of the pump and communicating with the suction passage 55. Recess 54 is associated with the pressure side of the pump and the passage 56 leads therefrom toward the center of the cover plate. For reasons which will be later explained the face of the pump housing 43 is formed with an annular groove 51. With the cover plate in position on said housing the groove communicates with the radial passages 58 formed in said plate and which extend to the periphery thereof.

The direction of rotation of the drive shaft 50 having been determined, the cover plate 5| is positioned on the pump housing 53 with the suction recess 53 in association with the suction side of the pump and the recess 5d in association with the pressure side of the pump. The oil under pressure is conducted through passage 56 to the central passage 60 formed in the stud 6| which has a pressed fit in the central opening 62 in the cover plate. Said stud is provided with a passage 63 extending to the periphery thereof at each side and which is at substantially right angles thereto although communicating with passage 60. The oil from the pressure side of the pump is discharged from passage 83 into the pressure chamber formed by the recess 23 and the flexible diaphragm 64. Said diaphragm is held to the inside face of the front cover 20 by the ring 65 securely bolted to said cover by screws 66. As shown in Figures 1, 2 and 6 the diaphragm 64 is held centrally to the cover plate 5!, being positioned between the cover plate and the stud 6|, which has a pressed fit in the central opening 62. The diaphragm has an opening therein slightly larger than the diameter of stud 6| so as to allow the pumping unit to align itself with respect to the diaphragm. The face of said stud BI is adapted to contact member 61 located within recess 26 provided therefor on the inside surface of the front cover 20. Said stud and the member form a valve which controls the flow of oil from the pressure chamber 23 to the passage 68, Figure 1, in the front cover 20 leading to the nozzle port l1.

The pumping unit of the present device has been previously described as free to move axially on the driving shaft 50. This movement is permitted by the flexible diaphragm 6 5 and when the movement is toward the right, Figure 1, it will be clearly understood that stud 6| is in retracted position with respect to member 61 so that the valve to the nozzle is open, allowing oil from the pressure chamber to flow to said nozzle. However, this retracted position of the stud 6| results when the hydrostatic pressure in chamber 23 is in excess of the tension exerted by the retaining spring .10. Said spring encircles the driving shaft 50, being located between the pump housing 43 which is recessed in its rear face for receiving the same and the stationary member II for the shaft seal 12. By means of the dowel pin 73 the member TI is prevented from rotating with respect to the casing of thepump. A gasket I5 is preferably located between the shoulder for the member II and said member to provide a seat therefor. The retaining spring 10 by exerting tension against the member 1! will hold the member firmly against the gasket 15 and the structure therefore provides a seal holding the oil within the suction chamber of the pump.

The retaining spring 10, which is in the form of a relatively .heavy coil spring, has other functions in addition to providing a force reacting against the hydrostatic pressure developed by the pump to thereby control the admission and cutoff of the flow of oil to the nozzle. Said spring, since it engages the pump housing, exerts sufficient force thereon, to prevent the housing from rotating with the shaft and with the pumping elements although in the event said elements freeze or become clogged with dirt said pump housing will rotate without any damage to any of the pump structure. Also said coil spring together with the flexible diaphragm 64 provides a flexible connection between the pump housing and the casing of the pump to confine the mechanical noise of the pump to the housing and said spring also facilitates in making the pump self-aligning with respect to the main bearing 14 which journals the driving shaft 50.

In operation of the pump of the present invention it will be assumed that the cover plate is associated with the pump housing 43 so that the direction of rotation of the shaft 50 is counter-clockwise when viewing the pump from the front as in Figure 3. Oil is supplied to the interior of the pump by the suction port I6 and is drawn through the screens 31 and 38 of relatively fine mesh which thoroughly strain the oil to be eventually conducted to "the pump through the suction passage 55. From the pressure side of the pump the oil flows into recess 54, passage 56, passages 6|] and 63, to be discharged into the pressure chamber. After the pump has been operating for a short period of time the hydrostatic pressure within the chamber, and which is against the diaphragm 64, will be sufficient to cause opening of the valve leading to the nozzle ll.

It will be understood that the pressure directed against the diaphragm 64 is communicated by said diaphragm to the pump housing 43, which may move axially on the driving shaft 50'. The tension of spring is, however, against the pressure and movement of the housing will take place only when the pressure exceeds the tension of the spring. The retaining spring H3 in combination with the flexible diaphragm 64 forms a valve automatically controlling the flow of the oil to the nozzle. forms one wall of the pressure chamber, additionally functions to eliminate the'pumping pulsations so that flow at the nozzle is more uniform than would otherwise be the case.

Even after the valve to the nozzle has opened the pump pressure continues to build up and will eventually force the cone valve 32 in an upward direction against the tension of spring 33. The oil which will thereupon flow past valve 32 and into passage 3| to the by-pass port l8 will represent the oil delivered by the pump in excess of that required by the nozzle. From the by-pass port t8 the oil may be returned to the tank which requires that said port have a connection leading to the tank. It is not necessary that the oil be returned to the tank, however. The port l8 may be closed and plug removed. As a result the oil is returned to the pump and is again circulatled thereby. The pressure required to lift the cone valve 32 may be adjusted by rotation of member 34. This member therefore controls the pressure of the oil delivered by the pump.

In-order to adapt the present pump to clockwise rotation of shaft 50 it is only necessary to The diaphragm 64, which is non-rotatably and releasably held to the pump housing 43 by the screw 52, the head ofwhich has location within an opening in the cover plate. When the position of the plate is rotated 180 degrees the screw is removed and threaded in an opening diametrically opposite its former position. This new rotated position of the plate will therefore associate the suction recess 53 with the suction side of the pump. The suction passage 55 from said recess has communication with a groove 51 in the face of the pump housing. Passages 58 in said plate and which extend to the periphery thereof also communicate with said groove. The function of these passages is to assure a minimum oil level within the pump irrespective of the position of the passage 55. In this connection, it must be borne in mind that the pumping unit including the housing and the pumping elements may rotate as a unit with shaft 5|]. This is a safety factor in case the pump gears freeze or in the event dirt should find its way to said gears or in the event the pump develops excessive hydraulic pressure; Since the rotative position of the pump housing and thus the cover 5| can not be predetermined the parts may be positioned with the suction passage 55 directed vertically downward. Were it not for the auxiliary passages all the oil would flow through 55 and the oil within the pump would be maintained at a low level below the shaft 50. However, as a result of the auxiliary passages in the groove 51 this can not happen.

In order to remove the pumping unit from the present'device it is only necessary to remove the front cover 20 of the pump casing. This cover is held to said casing by the screws 2|. Removal of the cover takes with it the diaphragm 64 and the cover plate 5| which, as explained, is releasably held to the pump housing. Said housing, the stationary seal member H and. the seal 12 may then be removed from the casing as a single unit. This removal of the pumping unit does not disturb the piping connections. After, inspection of the removed parts the same can be readily inserted within the casing and the front cover replaced, whereupon the pump is again ready for operation. In replacing the pumping unit the coil spring 10 will function to seat the stationary seal member II and said spring a so makes the pump unit self-aligning.

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings, as various other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

revolve the position of the cover plate 5| .180

' degrees with'respect to the central outlet passage 60. In accordance with the invention said plate What is claimed is: v

1. In a pump of the character described, in combination, a casing, a pumping unit housed within said casing, a drive shaft extending within the casing and operatively connecting with said pumping unit, a stationary seal mem-- her also housed by said casing providing a bearing for said shaft, a shaft seal having contact with the exterior'face of said member, a coil spring having engagement with the interior face and confined between said member and the pumping unit, and a removable cover for the casing in axial alignment with said shaft, whereby said shaft, pumping urit, coil spring, stationary seal member and shaft seal may be removed as a unit through the opening provided by removal of said cover.

2; In a pump of the character described, in

combination, a substantially tubular casing having an opening of large diameter at one end and a smaller opening at its opposite end, a removable cover for said opening of large diameter, a driving shaft extending within the casing through said smaller opening, a pumping unit mounted on the end of said shaft, said unit including driving and driven members, a pump housing enclosing said members, and a cover for the pump housing, a stationary seal member forming a closure for the small opening in said casing, a rotating seal element in contact with said stationary seal member, and a strainer within the casing having encircling relation with the pump housing for straining the fluid delivered to said unit, said strainer, pumping unit, shaft, seal member and rotating seal element being removable from the casing through said opening of large diameter.

3. In a pump of the character described, in combination, a casing providing an interior chamber and having a removable cover, a driv ing shaft extending into said chamber from the end opposite said cover, a pumping unit slidably mounted on the end of said shaft, means located within the chamber providing a bearing for the shaft, a coil spring confined between said means and said pumping unit whereby said unit is yieldingly forced axially of the shaft toward the said removable cover, a flexible diaphragm secured around its periphery to the inside face of said cover, said diaphragm being connected centrally thereof to the pumping unit and forming a chamber with said cover having communication with the pressure side of the pumping unit, and said cover having an outlet passage therein also communicating with said chamber.

4. In a pump of the character described, in combination, a casing" providing an interior chamber and having a removable cover, a driving shaft extending into said chamber from the end opposite said. cover, a pumping unit sliolably mounted on the end of said shaft, resilient means yieldingly forcing said pumping unit in a direction axially of the shaft toward said removable cover, a flexible diaphragm secured around its periphery to the inside face of said cover, said diaphragm having connection with the pumping unit centrally thereof and forming with. said cover a chamber communicating with the pressure side of the pumping unit, said cover having an outlet passage therein also communicating with said chamber, and said diphragm providing a valve normally maintaining said passage closed but having opening movement to permit the flow of fluid from the chamber to the passage when the fluid pressure within the chamber is greater than the tension exerted by said resilient means.

5. In a pump of the character described, in combination, a casing providing an interior chamber and having a removable cover, a driving shaft extending into said chamber from the end opposite said cover, a pumping unit mounted. on the end of said shaft, a flexible diphragm forming a pressure chamber with the inside face of the removable cover, said cligphragm having connection centrally thereof with the pumping unit and said chamber communicating with the pressure side of the pumping unit, said cover having an outlet passage also communicating with said chamber, and means fixed to said diaphragm forming a valve normally maintaining said passage closed but having movement in an opening direction to permit the flow of fluid from said chamber to the passage when a predetermined fluid pressure exists in said chamber.

6. In a pump of the character described, in combination, a casing providing an interior chamber and having a removable cover, a driving shaft extending into said chamber from the end opposite said cover, a pumping unit mounted on the end of said shaft, said unit including a pump housing, elements within the housing hav-' ing operative connection with the driving shaft providing a pump of the positive displacement type, and a cover plate having a suction and a pressure port therein, a flexible diaphragm fixed around its periphery to the inside surface of the removable cover and connecting centrally thereof with said cover plate, said diaphragm forming with said removable cover a chamber communicating with the pressure port in said cover plate, and said removable cover having an outlet passage therein also communicating with said chamber, said flexible diaphragm having movement to absorb the pumping pulsations whereby the fluid delivered to said passage has a substantially uniform pressure.

7. In a fuel pump, in combination, a casing providing an interior chamber and having a removable cover, a driving shaft extending into said chamber from the end opposite said cover, a pumping unit slidably mounted on the end of said shaft, 3, flexible diaphragm forming a pressure chamber with the inside face of the removable cover, said diaphragm having connection centrally thereof with the pumping unit, and said chamber communicating with the pressure side of the pumping unit through said connection, said cover having an outlet passage also communicating with the chamber, and said diaphragm providing a valve normally maintaining said passage closed but having movement in an opening direction to permit the flow of fluid from said chamber to the passage when a predetermined fluid pressure exists in said chamber.

8. In a fuel pump, in combination, a casing providing an interior chamber and having a removable cover, a driving shaft extending into said chamber from the end opposite said cover, a pumping unit slidably mounted on the end of said shaft, a flexible diaphragm forming a pressure chamber within the inside face of the removable cover, said diaphragm having connection centrally thereof with the pumping unit, and said chamber communicating with the pressure side of the pumping unit through said connection, said cover having an outlet passage also communicating with said chamber, means fixed to said diaphragm forming a valve normally maintaining said passage closed but having movement in an opening direction to permit the flow of fluid from said chamber to the passage when a predetermined pressure exists in said chamber, a second. passage in said cover communicating with said chamber to provide a by-pass for the fluid, valve means in the cover for said second passage, and resilient means yieldingly holding said valve means in closed position.

9. In a fuel pump, in combination, a casing providing an interior chamber and having a removable cover, a driving shaft extending into said chamber from the end opposite said cover, a pumping unit slidably mounted on the end of said shaft. a flexible diaphragm forming a pressure chamber with the inside face of the removable cover, means securing said diaphragm centrally thereof with the pumping unit and having a passage connecting said pressure chamber with piping connections for conducting the fluid to and from said pump, certain of said ports connecting with said outletpassage and said by-pass respectively.

10. In a fuel pump, in combination, a casing providing an interior chamber and having a removable cover, a driving shaft extending into said chamber from the end opposite said cover, a pumping unit mounted on the end of said shaft, said unit including a pump housing, elements within the housing having operative connection with the driving shaft providing a pump of the positive displacement type, and a cover plate releasably secured to said housing, said cover plate having a suction and a pressure port therein, and a coil spring in engagement with the face of said pump housing opposite the cover plate to thereby if suction chamber and a pressure chamber, said' pumping unit including a pump housing, elements within the housing having operative connection with the driving shaft providing a pump of the positive displacement type, and a cover plate for the pump housing having a suction opening communicating with the suction chamber and having-a pressure outlet communicating with the pressure chamber, whereby said flexible diaphragm will absorb the pumping pulsa-' tions by movement thereof so that the fluid delivered by thepump will have a substantially uniform pressure.

12. In a fuel pump, in combination, a casing having a removable cover forming with said casing an interior space, a driving shaft extending into said casing from theend opposite said cover, a pumping unit mounted on the end of said shaft, a flexible diaphragm within the casing forming a partition dividing the said interior space into a suction chamber and a, pressure chamber, said pumping unit including a pump housing, elements within the housing having operative connection with the. driving shaft providing a pump of the positive displacement type, and a cover plate for the puinp housing having securement to the said flexible diaphragm, said cover plate being provided with a suction opening communicating with the suction chamber and having a pressure outlet located centrally thereof and communicating with the pressure chamber, whereby the fleirible diaphragm will abs'orb the pumping pulsations by movement thereof so that the fluid delivered by the pump will have a substantially uniform pressure.

13. In a fuel pump, in combination, a casing having a removable cover forming with saidcasing an interior space, a driving shaft extending.

into said casing from the end opposite said cover, a pumping unit mounted on the end of said shaft, a flexible diaphragm within the casing forming a partition dividing the said interior space into a suction chamber and a pressure chamber, said pumping unit including a pump housing, elements within the housing having operative connection with the drivingshaft providing a pump of the positive displacement type, and a cover plate for the pump housing having a suction opening and a pressure outlet therein, means securing the cover plate centrally thereof to the flexible diaphragm and which provides a passage connecting the pressure outlet with said pressure chamber, whereby the flexible diaphragm will absorb the pumping pulsations by movement thereof so that the fluid delivered by the pump willhave a substantially uniform pressure, said cover plate having association with the pump' housing in, either of two rotated positions which vary by 180 degrees with respect to the shaft as the center of rotation thereby reversing the positions of the suction opening and pressure outlet with respect to the pumping elements in order to adapt said pumping unit for operation in either direction. i

14. In a pump of the character described, in combination, a casing, a pumping unit housed within said casing, a drive shaft extending within the casing and operatively connecting with said pumping unit, a stationary seal member also housed by said casing, a rotating seal element in contact with said stationary seal member, said casing having a relatively large opening in substantial alignment with the pumping unit, drive shaft and seal member, said seal member and pumping unit being insertable within the casing only through said opening and wherebysaid said casing providing piping connections for conducting the fluid to and from said pump, the insertion and removal of said parts through said relatively large opening being possible without disturbing said piping connections.

15. In a fuel pump, iii-combination, a casing providing an interior chamber and having a. re movable cover, a drive shaft extending into said chamber from the end opposite said cover, a pumping unit mounted on the end of said 'shaft, saidunit including a pump housing and elements within the housing for operative connection with the drive shaft providing a pump of the positive displacement type, and a cover plate for the pump providing a suction opening communicating with a suction zone surrounding the pumping unit and providing a pressure outlet communicating with a pressure chamber having a discharge outlet, said cover 'plate having association with the pump housing in either of two rotated positions with respect to the shaft as an axis and which vary by degrees, thereby reversing the positions of the suction opening and pressure outlet with respect to the pumping elements'in order to adapt said pumping unit for operation in either direction of rotation.

WILLIAM J. WAGNER, 

